Multiplexing data for multiple wireless transmit/receive units in a subframe

ABSTRACT

A method, apparatus, and system for multiplexing data for multiple wireless transmit/receive units (WTRUs) in a subframe are disclosed. A WTRU may receive a common control information message for a group of WTRUs time multiplexed in one subframe and a WTRU-specific control information message for a corresponding WTRU. The WTRU may determine whether the common control information message is directed to the WTRU based on a group WTRU identity. The WTRU may determine whether the WTRU-specific control information message is directed to the WTRU based on a WTRU-specific identity for the WTRU. The WTRU may receive a physical downlink shared channel on a WTRU-specific transmission time interval (TTI) within the subframe based on decoding common control information message with the group WTRU identity. The WTRU may decode the physical downlink shared channel using the common control information message and the WTRU-specific control information message for the WTRU.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/695,118 filed on Jul. 23, 2013 which is the U.S. National Stage,under 35 U.S.C. §371, of International Application No. PCT/US2011/034787filed May 2, 2011, which claims the benefit of U.S. Provisional PatentApplication No. 61/329,669 filed Apr. 30, 2010 and 61/329,996 filed Apr.30, 2010, the contents of which are hereby incorporated by referenceherein.

BACKGROUND

Communication systems using multiple antennas at both the transmitterand the receiver have been developed. Systems that utilize multipletransmit and receive antennas may be referred to as multiple-inputmultiple-output (MIMO) systems. The multi-antenna configurations may beutilized to mitigate the negative effects of multipath and signalinterference on signal reception. With the introduction of downlinkMIMO, a wireless transmit/receive unit (WTRU) may receive multiple datastreams simultaneously on the same frequency.

In high speed downlink packet access (HSDPA), downlink transmissions arescheduled by the Node B in a 2 ms transmission time interval (TTI)basis. In many cases there is not enough data for a single user to fullyfill a 2 ms TTI. Internet traffic studies have shown that quite a largenumber of packets are in the order of 2 or 4 kbits, topped with thedownlink traffic for cases like signaling radio bearer (SRB), voice overIP (VoIP) or transmission control protocol/Internet protocol (TCP/IP)acknowledgements for uplink traffic.

SUMMARY

Method and apparatus for multiplexing data for multiple wirelesstransmit/receive units (WTRUs) for high speed downlink channels aredisclosed. A WTRU may receive a joint high speed shared control channel(HS-SCCH) including a common part and WTRU-specific parts. The commonpart includes common control information for WTRUs multiplexed in onetransmission time interval (TTI), and each of the WTRU-specific partsincludes WTRU-specific control information for a corresponding WTRU. TheWTRU receives a high speed physical downlink shared channel (HS-PDSCH)based on decoding on the joint HS-SCCH.

In case data for multiple WTRUs are multiplexed into one medium accesscontrol (MAC) protocol data unit (PDU), the HS-SCCH may include a groupWTRU identity shared by a group of WTRUs. The WTRU may receive anHS-PDSCH based on decoding on the HS-SCCH with the group WTRU identity,and retrieve a MAC payload from the MAC PDU based on correspondingcontrol information in the MAC header on a condition that a dedicatedWTRU identity is detected in the MAC header.

A method, apparatus, and system for multiplexing data for WTRUs in asubframe are disclosed. A WTRU may receive a common control informationmessage for a group of WTRUs time multiplexed in one subframe and aWTRU-specific control information message for a corresponding WTRU. TheWTRU may be part of the group of WTRUs. The WTRU may determine whetherthe common control information message is directed to the WTRU based ona group WTRU identity. The WTRU may determine whether the WTRU-specificcontrol information message is directed to the WTRU based on aWTRU-specific identity for the WTRU. The WTRU may receive a physicaldownlink shared channel on a WTRU-specific transmission time interval(TTI) within the one subframe based on decoding of the common controlinformation message with the group WTRU identity, wherein theWTRU-specific TTI for the WTRU may be one of a plurality ofWTRU-specific TTIs within the same subframe. The WTRU may decode thephysical downlink shared channel using the common control informationmessage and the WTRU-specific control information message for the WTRU.Each WTRU-specific TTI may be specific to a corresponding WTRU or aplurality of WTRUs. Receiving the physical downlink shared channel mayalso be based on decoding the WTRU-specific control information with theWTRU-specific identity for the WTRU. The group WTRU identity may bedecoded using cyclic redundancy check (CRC) bits. One or more WTRUs thatmay comprise the group of WTRUs may be dynamically changed for eachtransport block.

BRIEF DESCRIPTION OF THE DRAWINGS

A more detailed understanding may be had from the following description,given by way of example in conjunction with the accompanying drawingswherein:

FIG. 1A is a system diagram of an example communications system in whichone or more disclosed embodiments may be implemented;

FIG. 1B is a system diagram of an example wireless transmit/receive unit(WTRU) that may be used within the communications system illustrated inFIG. 1A;

FIG. 1C is a system diagram of an example radio access network and anexample core network that may be used within the communications systemillustrated in FIG. 1A;

FIG. 2 is a conventional MAC-ehs PDU format;

FIG. 3 is an example MAC-ehs PDU format in one embodiment;

FIG. 4 shows another example MAC-ehs PDU format in another embodiment;

FIG. 5 shows an example MAC-ehs PDU and MAC-ehs header format in oneembodiment;

FIG. 6 shows an example final MAC-ehs PDU format in one embodiment;

FIG. 7 shows an MAC-ehs entity on the WTRU side;

FIG. 8 shows an example MAC-ehs entity on the WTRU side supportingMAC-ehs PDU multiplexing in case individual WTRU MAC-ehs PDUs aremultiplexed into a final MAC-ehs PDU;

FIG. 9 is an example MAC-ehs entity on the UTRAN side supporting WTRUmultiplexing in one embodiment;

FIG. 10 shows multiple WTRUs scheduled within a single 2 ms TTI usingcode division multiplexing (CDM);

FIG. 11 shows multiple WTRUs scheduled in a single 2 ms TTI using timedivision multiplexing (TDM);

FIG. 12 shows example slot-wise HS-SCCH signaling scheme and timingrelationship between HS-SCCH and HS-PDSCH;

FIG. 13 is an example flow diagram of HS-SCCH encoding for a non-MIMOmode;

FIG. 14 is an example flow diagram of HS-SCCH encoding for an MIMO mode;

FIGS. 15 and 16 are example flow diagrams of HS-SCCH encoding for anon-MIMO mode and an MIMO mode, respectively;

FIG. 17 shows an example encoding chain of the joint HS-SCCH for anon-MIMO mode; and

FIG. 18 shows an example encoding chain of the joint HS-SCCH for an MIMOmode.

DETAILED DESCRIPTION

The embodiments herein will be described with reference to the figureswherein like element numbers represent like elements throughout.

FIG. 1A is a diagram of an example communications system 100 in whichone or more disclosed embodiments may be implemented. The communicationssystem 100 may be a multiple access system that provides content, suchas voice, data, video, messaging, broadcast, etc., to multiple wirelessusers. The communications system 100 may enable multiple wireless usersto access such content through the sharing of system resources,including wireless bandwidth. For example, the communications systems100 may employ one or more channel access methods, such as code divisionmultiple access (CDMA), time division multiple access (TDMA), frequencydivision multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrierFDMA (SC-FDMA), and the like.

As shown in FIG. 1A, the communications system 100 may include wirelesstransmit/receive units (WTRUs) 102 a, 102 b, 102 c, 102 d, a radioaccess network (RAN) 104, a core network 106, a public switchedtelephone network (PSTN) 108, the Internet 110, and other networks 112,though it will be appreciated that the disclosed embodiments contemplateany number of WTRUs, base stations, networks, and/or network elements.Each of the WTRUs 102 a, 102 b, 102 c, 102 d may be any type of deviceconfigured to operate and/or communicate in a wireless environment. Byway of example, the WTRUs 102 a, 102 b, 102 c, 102 d may be configuredto transmit and/or receive wireless signals and may include userequipment (UE), a mobile station, a fixed or mobile subscriber unit, apager, a cellular telephone, a personal digital assistant (PDA), asmartphone, a laptop, a netbook, a personal computer, a wireless sensor,consumer electronics, and the like.

The communications systems 100 may also include a base station 114 a anda base station 114 b. Each of the base stations 114 a, 114 b may be anytype of device configured to wirelessly interface with at least one ofthe WTRUs 102 a, 102 b, 102 c, 102 d to facilitate access to one or morecommunication networks, such as the core network 106, the Internet 110,and/or the networks 112. By way of example, the base stations 114 a, 114b may be a base transceiver station (BTS), a Node-B, an eNode B, a HomeNode B, a Home eNode B, a site controller, an access point (AP), awireless router, and the like. While the base stations 114 a, 114 b areeach depicted as a single element, it will be appreciated that the basestations 114 a, 114 b may include any number of interconnected basestations and/or network elements.

The base station 114 a may be part of the RAN 104, which may alsoinclude other base stations and/or network elements (not shown), such asa base station controller (BSC), a radio network controller (RNC), relaynodes, etc. The base station 114 a and/or the base station 114 b may beconfigured to transmit and/or receive wireless signals within aparticular geographic region, which may be referred to as a cell (notshown). The cell may further be divided into cell sectors. For example,the cell associated with the base station 114 a may be divided intothree sectors. Thus, in one embodiment, the base station 114 a mayinclude three transceivers, i.e., one for each sector of the cell. Inanother embodiment, the base station 114 a may employ multiple-inputmultiple output (MIMO) technology and, therefore, may utilize multipletransceivers for each sector of the cell.

The base stations 114 a, 114 b may communicate with one or more of theWTRUs 102 a, 102 b, 102 c, 102 d over an air interface 116, which may beany suitable wireless communication link (e.g., radio frequency (RF),microwave, infrared (IR), ultraviolet (UV), visible light, etc.). Theair interface 116 may be established using any suitable radio accesstechnology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 104 and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (UTRA), whichmay establish the air interface 116 using wideband CDMA (WCDMA). WCDMAmay include communication protocols such as High-Speed Packet Access(HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed DownlinkPacket Access (HSDPA) and/or High-Speed Uplink Packet Access (HSUPA).

In another embodiment, the base station 114 a and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Evolved UMTSTerrestrial Radio Access (E-UTRA), which may establish the air interface116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.16 (i.e.,Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000,CDMA2000 1×, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), InterimStandard 95 (IS-95), Interim Standard 856 (IS-856), Global System forMobile communications (GSM), Enhanced Data rates for GSM Evolution(EDGE), GSM EDGE (GERAN), and the like.

The base station 114 b in FIG. 1A may be a wireless router, Home Node B,Home eNode B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, and the like. In oneembodiment, the base station 114 b and the WTRUs 102 c, 102 d mayimplement a radio technology such as IEEE 802.11 to establish a wirelesslocal area network (WLAN). In another embodiment, the base station 114 band the WTRUs 102 c, 102 d may implement a radio technology such as IEEE802.15 to establish a wireless personal area network (WPAN). In yetanother embodiment, the base station 114 b and the WTRUs 102 c, 102 dmay utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG. 1A,the base station 114 b may have a direct connection to the Internet 110.Thus, the base station 114 b may not be required to access the Internet110 via the core network 106.

The RAN 104 may be in communication with the core network 106, which maybe any type of network configured to provide voice, data, applications,and/or voice over internet protocol (VoIP) services to one or more ofthe WTRUs 102 a, 102 b, 102 c, 102 d. For example, the core network 106may provide call control, billing services, mobile location-basedservices, pre-paid calling, Internet connectivity, video distribution,etc., and/or perform high-level security functions, such as userauthentication. Although not shown in FIG. 1A, it will be appreciatedthat the RAN 104 and/or the core network 106 may be in direct orindirect communication with other RANs that employ the same RAT as theRAN 104 or a different RAT. For example, in addition to being connectedto the RAN 104, which may be utilizing an E-UTRA radio technology, thecore network 106 may also be in communication with another RAN (notshown) employing a GSM radio technology.

The core network 106 may also serve as a gateway for the WTRUs 102 a,102 b, 102 c, 102 d to access the PSTN 108, the Internet 110, and/orother networks 112. The PSTN 108 may include circuit-switched telephonenetworks that provide plain old telephone service (POTS). The Internet110 may include a global system of interconnected computer networks anddevices that use common communication protocols, such as thetransmission control protocol (TCP), user datagram protocol (UDP) andthe internet protocol (IP) in the TCP/IP internet protocol suite. Thenetworks 112 may include wired or wireless communications networks ownedand/or operated by other service providers. For example, the networks112 may include another core network connected to one or more RANs,which may employ the same RAT as the RAN 104 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities, i.e., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks. For example, the WTRU 102 c shown in FIG. 1A may be configured tocommunicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram of an example WTRU 102. As shown in FIG. 1B,the WTRU 102 may include a processor 118, a transceiver 120, atransmit/receive element 122, a speaker/microphone 124, a keypad 126, adisplay/touchpad 128, non-removable memory 106, removable memory 132, apower source 134, a global positioning system (GPS) chipset 136, andother peripherals 138. It will be appreciated that the WTRU 102 mayinclude any sub-combination of the foregoing elements while remainingconsistent with an embodiment.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it will be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, thetransmit/receive element 122 may be an antenna configured to transmitand/or receive RF signals. In another embodiment, the transmit/receiveelement 122 may be an emitter/detector configured to transmit and/orreceive IR, UV, or visible light signals, for example. In yet anotherembodiment, the transmit/receive element 122 may be configured totransmit and receive both RF and light signals. It will be appreciatedthat the transmit/receive element 122 may be configured to transmitand/or receive any combination of wireless signals.

In addition, although the transmit/receive element 122 is depicted inFIG. 1B as a single element, the WTRU 102 may include any number oftransmit/receive elements 122. More specifically, the WTRU 102 mayemploy MIMO technology. Thus, in one embodiment, the WTRU 102 mayinclude two or more transmit/receive elements 122 (e.g., multipleantennas) for transmitting and receiving wireless signals over the airinterface 116.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 106 and/or the removable memory 132.The non-removable memory 106 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chip set 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 116 from abase station (e.g., base stations 114 a, 114 b) and/or determine itslocation based on the timing of the signals being received from two ormore nearby base stations. It will be appreciated that the WTRU 102 mayacquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, and the like.

FIG. 1C is a system diagram of the RAN 104 and the core network 106according to an embodiment. As noted above, the RAN 104 may employ aUTRA radio technology to communicate with the WTRUs 102 a, 102 b, 102 cover the air interface 116. The RAN 104 may also be in communicationwith the core network 106. As shown in FIG. 1C, the RAN 104 may includeNode-Bs 140 a, 140 b, 140 c, which may each include one or moretransceivers for communicating with the WTRUs 102 a, 102 b, 102 c overthe air interface 116. The Node-Bs 140 a, 140 b, 140 c may each beassociated with a particular cell (not shown) within the RAN 104. TheRAN 104 may also include RNCs 142 a, 142 b. It will be appreciated thatthe RAN 104 may include any number of Node-Bs and RNCs while remainingconsistent with an embodiment.

As shown in FIG. 1C, the Node-Bs 140 a, 140 b may be in communicationwith the RNC 142 a. Additionally, the Node-B 140 c may be incommunication with the RNC 142 b. The Node-Bs 140 a, 140 b, 140 c maycommunicate with the respective RNCs 142 a, 142 b via an Iub interface.The RNCs 142 a, 142 b may be in communication with one another via anIur interface. Each of the RNCs 142 a, 142 b may be configured tocontrol the respective Node-Bs 140 a, 140 b, 140 c to which it isconnected. In addition, each of the RNCs 142 a, 142 b may be configuredto carry out or support other functionality, such as outer loop powercontrol, load control, admission control, packet scheduling, handovercontrol, macrodiversity, security functions, data encryption, and thelike.

The core network 106 shown in FIG. 1C may include a media gateway (MGW)144, a mobile switching center (MSC) 146, a serving GPRS support node(SGSN) 148, and/or a gateway GPRS support node (GGSN) 150. While each ofthe foregoing elements are depicted as part of the core network 106, itwill be appreciated that any one of these elements may be owned and/oroperated by an entity other than the core network operator.

The RNC 142 a in the RAN 104 may be connected to the MSC 146 in the corenetwork 106 via an IuCS interface. The MSC 146 may be connected to theMGW 144. The MSC 146 and the MGW 144 may provide the WTRUs 102 a, 102 b,102 c with access to circuit-switched networks, such as the PSTN 108, tofacilitate communications between the WTRUs 102 a, 102 b, 102 c andtraditional land-line communications devices.

The RNC 142 a in the RAN 104 may also be connected to the SGSN 148 inthe core network 106 via an IuPS interface. The SGSN 148 may beconnected to the GGSN 150. The SGSN 148 and the GGSN 150 may provide theWTRUs 102 a, 102 b, 102 c with access to packet-switched networks, suchas the Internet 110, to facilitate communications between and the WTRUs102 a, 102 b, 102 c and IP-enabled devices.

As noted above, the core network 106 may also be connected to thenetworks 112, which may include other wired or wireless networks thatare owned and/or operated by other service providers.

It should be noted that even though embodiments are described in thecontext of 3GPP UMTS wireless communications systems, the embodimentsmay be applied to any wireless communication systems, such as long termevolution (LTE), LTE Advanced, GPRS EDGE radio access network (GERAN)and WiMax, etc. It should be noted that the embodiments are describedwith reference to HS-DSCH and MAC-ehs, but the embodiments areapplicable to any other types of transport channels and MAC entities.The embodiments disclosed herein may be used independently or in anycombination.

HS-DSCH data for multiple WTRUs may be included in one MAC transportblock, (e.g., MAC-ehs PDU). Before a transport block, (i.e., MAC-ehsPDU), is received on the HS-DSCH by the WTRU, the HS-SCCH which includesthe demodulation and hybrid automatic repeat request (HARQ) informationas well as the WTRU identity needs to be decoded (layer 1 addressing).If the WTRU identity on the HS-SCCH matches, the layer 1 forwards thetransport block to the MAC layer. The MAC layer then determines whichHS-DSCH data included in the MAC-ehs PDU belongs to the WTRU (layer 2addressing).

Embodiments for layer 1 addressing, (i.e., identifying the WTRUs for theMAC-ehs PDU), are disclosed hereafter.

In one embodiment, a common WTRU identity shared by multiple WTRUs maybe used for layer 1 addressing. The common WTRU identity may be a groupWTRU identity. For example, a group HS-DSCH radio network temporaryidentity (H-RNTI) may be assigned to a group of WTRUs by the network,for example, via a radio resource control (RRC) configuration orreconfiguration message or via a layer 1 signaling, (e.g., HS-SCCHorder). This group WTRU identity may be signaled via the HS-SCCH toindicate which WTRUs the MAC-ehs PDU is addressed to. If its assignedgroup WTRU identity is decoded on the HS-SCCH, the layer 1 receives thecorresponding HS-DSCH and forwards the HS-DSCH transport block to theMAC layer.

Alternatively, the WTRU may be pre-configured with different group WTRUidentities via RRC signaling and the network may dynamically change thegroup WTRU identity of the WTRU, (e.g., via an HS-SCCH order), by usingan index into one of the group WTRU identities.

Alternatively, the WTRU may be provided with an additional WTRUidentity, (called a multiplexing WTRU identity), in addition to aregular WTRU identity. For instance, a primary H-RNTI and a secondaryH-RNTI may be assigned to a WTRU, where the secondary H-RNTI may be usedfor multiplexing multiple WTRUs in a TTI. The multiplexing WTRU identitymay be signaled through the HS-SCCH in case the network multiplexes datafor different WTRUs in one HS-DSCH transport block.

Alternatively, the WTRU may determine the group WTRU identity from thededicated WTRU identity in accordance with a predetermined rule known byboth the WTRU and the network. For example, the dedicated WTRU identitymay be masked by a predetermined value to derive the group WTRUidentity. For example, a group of WTRUs may share certain bits of theirdedicated H-RNTIs, (e.g., 12 most significant bits (MSBs)). In thiscase, the WTRUs may determine their group H-RNTI by performing thelogical operation: H-RNTI AND FFFOh.

In another embodiment, a new HS-SCCH format may be defined to indicate alist of WTRU identities, (e.g., H-RNTIs). For example, a list of WTRUidentities for multiple WTRUs may be signaled via the HS-SCCH. Forinstance, in one example assuming 16 bits for each H-RNTI, the WTRUidentity field may be extended for multiplexing two WTRUs as follows:x_(wtru1,1), x_(wtru2,2), . . . , x_(wtru1,16), . . . , x_(wtruk,1),x_(wtruk,2), . . . , x_(wtruk,16) When decoding the HS-SCCH, the layer 1determines which WTRUs the HS-DSCH data is addressed to from the list ofWTRU identities included in the HS-SCCH and may forward the HS-DSCHtransport block to the MAC layer if its own WTRU identity is included inthe list of WTRU identities. Alternatively, the WTRU may be addressed bymeans of having one common WTRU identity that may be used in the HS-SCCHand an index to a WTRU in the group that may uniquely identify the WTRUwhich is being scheduled. A list of indices of all multiplexed WTRUs maybe provided in the HS-SCCH.

The number of WTRUs that may be addressed in the same HS-DSCH transportblock may be predefined, (e.g., two WTRUs). This number may beconfigured at the RRC or layer 1 level.

Alternatively, the number of WTRUs that are addressed in the sameHS-DSCH transport block may be dynamically changed. There may be amaximum number of WTRUs that may be addressed simultaneously. The layer1 determines how many WTRU identities are present in the HS-SCCH inaccordance with one or a combination of the following embodiments.

An additional field may be included in the HS-SCCH to indicate how manyWTRU identities are included in the HS-SCCH. The layer 1 may decode thecorresponding number of bits in the HS-SCCH in accordance with theadditional field and may ignore the rest of the WTRU address bits. Forexample, if maximum three WTRUs may be addressed at the same time andthe network multiplexes data for two WTRUs in one HS-DSCH transportblock and therefore sets the additional field to indicate two WTRUs aremultiplexed, the layer 1 may decode 32 bits (assuming 16 bits of WTRUidentity) and discard the remaining 16 bits. Alternatively, certainvalues of the H-RNTI, (e.g., all zeros or all ones), may be reserved toindicate that this is not a valid H-RNTI. Depending on the number ofvalid H-RNTIs decoded, the layer 1 may determine the number of WTRUsbeing addressed.

Embodiments for layer 2 addressing, (i.e., identifying the WTRUs foreach of the HS-DSCH data included in the MAC-ehs PDU), are disclosedhereafter. In order to address multiple WTRUs in the same transportblock, the MAC-ehs PDU header may include new fields so that the MACentity may extract its own payload.

In accordance with one embodiment, the MAC-ehs header may include one ormore WTRU identities for each HS-DSCH data multiplexed in the HS-DSCHtransport block. The WTRU identities may be added in the same order thatthe MAC-ehs payloads are concatenated in the MAC-ehs PDU. Morespecifically, if WTRU ID1 appears first in the MAC-ehs header, then thecorresponding reordering PDU(s) or MAC-ehs payload for UE1 may beconcatenated first in the MAC-ehs PDU, and so on.

The WTRU ID used for layer 2 addressing to identify the WTRU for eachHS-DSCH payload included in the MAC transport block may be the H-RNTI ofthe WTRU, the primary E-DCH radio network temporary identity (E-RNTI) ofthe WTRU, or any other types of WTRU identity. Alternatively, the WTRUID for layer 2 addressing may be a subset of the H-RNTI or any WTRUidentity. In case a certain number of bits of the WTRU identity arecommon among several WTRUs and used for layer 1 addressing, theremaining bits are unique for each WTRU and may be used for layer 2addressing for each HS-DSCH payload multiplexed in the HS-DSCH transportblock. A logical AND operation between the WTRU identity and a mask maybe performed to obtain this subset of dedicated bits for layer 2addressing. For instance, in case 12 bits of WTRU identity are commonand 4 bits are unique to each WTRU, the logical operation may be asfollows: WTRU Identity AND 000Fh.

Alternatively, each WTRU within a group may be assigned an identity oran index number. This identity may require less bits than the H-RNTI,(e.g., if 16 or 8 WTRUs may be included in one group, 4 or 3 bits,respectively, may be used to uniquely identify the WTRUs in the group).This will reduce the overhead associated to addressing the WTRUs in theMAC header. This WTRU ID may be signaled to the WTRU as part of the RRCconfiguration or alternatively, a predefined rule may be used.

The index may take a value equal to the number of WTRUs being addressedin the same transport block. For instance, if three WTRUs are addressed,the index may take the values 0, 1, or 2. Layer 1 may determine, andprovide, the index number to the MAC layer. For example, if layer 1decodes the WTRU identity at the n-th place, layer 1 may indicate index‘n’ to the MAC layer. Alternatively, the network may use differentHS-SCCHs configured for a WTRU to indicate this index. Conventionally,up to four HS-SCCHs may be configured per carrier for a WTRU. The indexmay be determined based on the HS-SCCH number that the WTRU decodes itsgroup WTRU identity or individual WTRU identity. For instance, ifHS-SCCH1 is used, the WTRU may use the index1, if HS-SCCH2 is used, theWTRU may use index2, and so on. Alternatively, in case where data fortwo WTRUs are multiplexed in one HS-DSCH transport block, the parity ofthe HS-SCCH may be used to indicate which index to use to extract itsMAC-ehs payload. For instance, if the HS-SCCH used is an odd number, theWTRU may use index1, while if the HS-SCCH used is an even number, theWTRU may use index2, or vice-versa.

It should be understood that even though the WTRU addressing isdescribed as part of layer 2 addressing, they may be equally applicablefor layer 1 addressing.

FIG. 2 is a conventional MAC-ehs PDU format. A MAC-ehs PDU includes anMAC-ehs header and an MAC-ehs payload. The MAC-ehs header includesextraction information for the payload. The MAC-ehs payload may includeone or multiple reordering PDUs. Each reordering PDU may includecomplete or segmented reordering service data units (SDUs). The MAC-ehsheader includes one or more sets of logical channel identity (LCH-ID),length (L), transmission sequence number (TSN), segmentation information(SI), and flag (F) fields. The LCH-ID and L fields are repeated perreordering SDU. The TSN and SI fields are repeated per reordering PDU.The LCH-ID field in the MAC-ehs header indicates to which logicalchannel each reordering SDU belongs to. The L field indicates the lengthin bytes of each reordering SDU. The TSN field and the SI fieldindicates if and how the reordering PDU has been segmented in multiplereordering SDUs. The flag F indicates if it is the end of the MAC-headeror if the next field is another LCH-ID. The presence of the TSN_(i) andSI_(i) fields is based on the value of the LCH-ID_(i). If the LCH-ID_(i)is mapped to the same reordering queue as LCH-ID_(i-1) or if the valueof LCH-ID_(i-1) is equal to the value of LCH-ID_(i), there is no TSN_(i)or SI_(i) field. The mapping of the LCH-ID to the reordering queue isprovided by upper layers.

Embodiments for MAC-ehs PDU and MAC-ehs header format are disclosedhereafter.

In one embodiment, the reordering PDUs belonging to one WTRU may bearranged in the MAC-ehs PDU consecutively and one MAC-ehs header at thebeginning of the MAC-ehs PDU may include field(s) indicating whichreordering PDU(s) belong to which WTRU. The MAC-ehs header may include aWTRU address field, a length field indicating the length of the WTRUMAC-ehs payload or the number of reordering PDUs, and a flag(s).

In one embodiment, each set of LCH-ID and L fields may be followed by aflag (FLAG), (e.g., one-bit flag), which indicates whether the followingfield is a WTRU address field (WTRU-ID) or an LCH-ID field. For example,if FLAG is set to ‘1’, the next field is a WTRU address field (WTRU-ID),and if FLAG is set to ‘0’, the next fields are a new set of LCH-ID and Lfields corresponding to the same WTRU or it is the end of the MAC-ehsPDU. In case the TSN and SI fields are present, this new flag may beadded after the SI field. Alternatively, the WTRU-ID and FLAG may beincluded in any location in the MAC-ehs header.

The WTRU needs to distinguish between the end of one WTRU MAC-ehspayload and the end of the MAC-ehs header. The MAC layer may know thenumber of WTRUs in advance via layer 1, or a new field may be added inthe MAC-ehs header to indicate the number of WTRUs multiplexed in theMAC-ehs PDU. Alternatively, instead of a one-bit flag (FLAG), a two-bitflag may be used to indicate whether the next field is a WTRU address,an LCH-ID, or the end of the MAC-ehs header (or alternatively, a fieldF).

Alternatively, the MAC-ehs header may include WTRU address fields(WTRU-ID_(i)) and a length field (L_(UE)) indicating the number of bitsor bytes of data belonging to each WTRU. A one-bit flag may be added atthe end of each set of WTRU address and L_(UE) fields to indicatewhether the following field is a new set of WTRU-ID and L_(UE) fields orthere is no more WTRU being addressed. The number of multiplexed WTRUsmay be fixed and may not be signaled via the MAC-ehs header.Alternatively, the number of multiplexed WTRUs may vary and the MAC-ehsheader may include an N field indicating the number of WTRUs multiplexedin the MAC-ehs PDU. Alternatively, the number of multiplexed WTRUs maybe signaled via the HS-SCCH. Layer 1 may determine the number of WTRUsand forwards this number to the MAC layer.

Alternatively, the length of the data for each WTRU may be one ofpredefined numbers, that may be configurable, and it may be indicated inthe HS-SCCH. Alternatively, the length of the data for each WTRU maycorrespond to all or a subset of values of the transport block table andthe L_(UE) field may correspond to an index of the entries of thetransport block table. Alternatively, the number of reordering PDUs maybe indicated for each WTRU instead of a length L_(UE).

Alternatively, one WTRU address field may be added in the MAC-ehs headerper reordering PDU. A new flag may be added after each LCH-ID and Lfields to indicate whether the following field is the LCH-ID or WTRUaddress. Alternatively, a new flag may be added after the LCH-ID and Lfields in case the LCH-ID value is different from the previous one. Theflag may be added after the first LCH-ID and L fields. This flag mayindicate to the MAC layer if the next field is a WTRU address field oran LCH-ID field. The same value of the WTRU address field may berepeated.

Alternatively, one WTRU address may be added in the MAC-ehs header perreordering SDU, which means that one WTRU address field is added aftereach LCH-ID and L fields. In this case, no new flag may be requiredsince the MAC layer may expect a WTRU address field after each set ofLCH-ID and L fields, or TSN if present) and SI (if present) fields.Alternatively, the WTRU address field may be added before the LCH-IDfield.

FIG. 3 is an example MAC-ehs PDU format in one embodiment. The MAC-ehsPDU 300 includes an MAC-ehs header 310 and MAC-ehs payloads 330 for aplurality of WTRUs. The MAC-ehs header 310 includes an LCH-ID field 312,L field 314, TSN field 316, SI field 318, FLAG 320, WTRU ID 322, and Ffield 324. The MAC-ehs payload 320 includes reordering PDUs for aplurality of WTRUs. FLAG 320 and WTRU-ID 322 are added in the MAC-ehsheader 310 after the set of LCH-ID 312, L 314, TSN 316 and SI 318, (orLCH-ID and L fields if TSN and SI field are not present). The FLAG field320 may be added per reordering SDU to indicate if the next field is anew WTRU-ID or a new LCH-ID. The WTRU-ID field 322 is added per WTRUpayload, (i.e., the number of WTRU-ID fields correspond to the number ofmultiplexed WTRUs in the MAC-ehs PDU). To extract its payload, the MAClayer compares the WTRU-ID field to its own WTRU identity, and if theymatch, the MAC layer extracts the reordering PDUs as long as the fieldFLAG 320 indicates the next field is not a new WTRU-ID. If the fieldFLAG 320 indicates that the next field is another WTRU-ID, the MAC layerstops extracting the corresponding reordering PDUs.

FIG. 4 shows another example MAC-ehs PDU format in another embodiment.The MAC-ehs PDU 400 includes an MAC-ehs header 410 and a payload 430.The MAC-ehs header 410 includes an N field 412, WTRU-ID fields 414,L_(UE) fields 416, an LCH-ID field 418, L field 420, TSN field 422, SIfield 424, and F field 426. The payload 430 includes reordering PDUs fora plurality of WTRUs. The N field 412 indicates the number ofmultiplexed WTRUs in the MAC-ehs PDU. The list of WTRU-IDs 414 andL_(UE) fields 416 (indicating the length of each WTRU payload) may beadded at the beginning of the MAC-ehs header. To extract its payload,the MAC layer reads the fields in the header and stores each L_(UE)until if finds its own WTRU-ID. The MAC layer continues to read theheader and adds up the L fields it encounters until it reaches thelength of the WTRU payloads preceding its own payload (using the L_(UE)fields of the preceding WTRUs). The MAC layer then extracts its payload,knowing its own L_(UE) length.

In another embodiment, a MAC-ehs header may be added before each MAC-ehspayload for WTRU. This MAC-ehs header may include the WTRU address,(e.g., WTRU identity, sub-identity, index, or the like). Alternatively,no new field may be added in each MAC-ehs header and the MAC layer maydetermine in which position its own MAC-ehs header is based on anindication from layer 1.

FIG. 5 shows an example MAC-ehs PDU and MAC-ehs header format in oneembodiment. In this example, a MAC-ehs header 510 is added to an MAC-ehspayload 530 for each WTRU. Each MAC-ehs header 510 includes an WTRU-IDfield 512, an LCH-ID field 514, an L field 516, a TSN field 518, an SIfield 520, and an F field 522. The WTRU-ID field 512 indicates to whichWTRU the following MAC-ehs payload belongs. The MAC layer reads theMAC-ehs header 510 until it finds its own WTRU-ID, and then extracts itspayload. Padding bits may be added at the end the MAC-ehs PDU, oralternatively at the end of each MAC-ehs payload.

In another embodiment, individual WTRU MAC-ehs PDUs (including payloadand header) are first created for the WTRUs that are multiplexed in theMAC-ehs transport block, and the individual WTRU MAC-ehs PDUs aremultiplexed into a final MAC-ehs PDU. A final MAC-ehs PDU header may beadded to each individual WTRU MAC-ehs PDU. On the WTRU side, the WTRUde-multiplexes the individual WTRU MAC-ehs PDUs based on the finalMAC-ehs PDU headers. If the WTRU determines that one of the individualWTRU MAC-ehs PDUs is addressed to itself, the WTRU may disassemble thatindividual WTRU MAC-ehs PDU for further processing, and may discardother individual WTRU MAC-ehs PDUs.

FIG. 6 shows an example final MAC-ehs PDU format in one embodiment. Thefinal MAC-ehs PDU 600 includes final MAC-ehs PDU headers 610 andindividual WTRU MAC-ehs PDUs 620. The final MAC-ehs PDU headers 610 maybe arranged at the beginning of the final MAC-ehs PDU 600. Theindividual WTRU MAC-ehs PDU 620 includes an MAC-ehs header 630 andreordering PDUs 650 for each WTRU.

The final MAC-ehs PDU header 610 for each individual WTRU MAC-ehs PDUmay include an WTRU identity (WTRU-ID) 612, and a length field (L_(UEx))614 indicating the length of the individual WTRU MAC-ehs PDU 620 forUEx. The length may be expressed in units of bytes or bits, oralternatively may correspond to an index to a pre-defined set of MAC-ehsPDU sizes, (e.g., all or subset of transport block table). The lengthfield is used to de-multiplex the individual WTRU MAC-ehs PDUs.

The final MAC-ehs PDU header 610 may include a flag (not shown), (e.g.,at the end of each final MAC-ehs PDU header), to indicate whether thisis the end of the final MAC-ehs PDU header 610 or a more WTRU ID orL_(UE) follows. The final MAC-ehs PDU header 610 may include a field(not shown) to indicate how many individual WTRU MAC-ehs PDUs aremultiplexed together in the final MAC-ehs PDU 600. For example, an Nfield may be added in the final MAC-ehs PDU header 610. Alternatively,the L field may signal this value to the WTRU. Alternatively, the numberof multiplexed WTRUs may be predetermined and known to the WTRU.

Alternatively, the HS-SCCH may indicate the individual WTRU MAC-ehs PDUsize in the final MAC-ehs PDU. In this case, the L_(UE) field may not bepresent in the final MAC-ehs header. The WTRU retrieves the multiplexedindividual WTRU MAC-ehs PDU size over the HS-SCCH and together with theWTRU ID in the final MAC-ehs PDU header, and de-multiplexes theindividual WTRU MAC-ehs PDU that belongs to the WTRU and discards otherindividual WTRU MAC-ehs PDUs.

Alternatively, the de-multiplexing information that is required by theMAC layer to extract its own reordering PDUs may be indicated in theHS-SCCH, which is forwarded by layer 1. This information may include thelength of each MAC-ehs payload per WTRU, (or the transport block sizefor each individual WTRU MAC-ehs PDU), or the number of MAC-ehsreordering PDUs per WTRU. Layer 1 may extract the de-multiplexinginformation addressed to the WTRU and pass it to the MAC layer, or maypass to the MAC layer the de-multiplexing information addressed to theWTRUs. Alternatively, the size of the payload corresponding to each WTRUmay be predefined, (e.g., it may be the total transport block size ortotal payload divided by the number of WTRUs).

The MAC layer determines which MAC header or PDU format to use. If theWTRU has been assigned a group WTRU identity, (e.g., a group H-RNTI), ora multiplexing WTRU identity, (e.g., a secondary H-RNTI), and if layer 1decodes this identity in the HS-SCCH, the MAC layer may process with theMAC header format for WTRU multiplexing. Alternatively, the same MAC-ehsformat may be used regardless of the WTRU multiplexing. Alternatively,layer 1 may indicate to the MAC layer if more than one WTRU identity hasbeen decoded in the HS-SCCH so that the MAC layer may use the correctMAC header format. Alternatively, the MAC header format may be part ofan RRC configuration.

The network may use a different MAC-ehs PDU format depending on the typeof the transmission. If it is a transmission for a single WTRU, it mayuse the conventional MAC-ehs format and if it is a transmission formultiple WTRUs with data multiplexed in one transport block, it may usethe new format of the MAC-ehs PDU for multiplexing. Alternatively, thenetwork may use the same format and the WTRU may determine if the datais multiplexed or not by detecting the number of WTRUs being addressed.The network may dynamically multiplex the data for a different number ofWTRUs at different periods of time.

An HS-SCCH order may be used to explicitly enable the WTRU to startreception in this mode, (e.g., WTRUs are multiplexed and startre-interpreting the MAC or the HS-SCCH). The HS-SCCH order may containspecific information for the WTRU to use in order to start reception inthis mode. For example, the HS-SCCH order may assign a WTRU index orWTRU ID to use to identify itself within the group. Alternatively, theHS-SCCH may provide the group ID to the WTRU.

Embodiments for the MAC-ehs architecture on the WTRU and on the UTRANsides for supporting the multiplexing of WTRUs for HS-DSCH are disclosedhereafter.

FIG. 7 shows an MAC-ehs entity on the WTRU side. The HARQ entity 702 isresponsible for handling the HARQ protocol. The disassembly entity 704disassembles the MAC-ehs PDUs by removing the MAC-ehs header andpadding. The reordering queue distribution entity 706 routes thereceived reordering PDUs to correct reordering queues based on thereceived logical channel identifier. The reordering entity 708 organizesreceived reordering PDUs according to the received TSN. Data blocks withconsecutive TSNs are delivered to the reassembly entity upon reception.The reassembly entity 710 reassembles segmented MAC-ehs SDUs andforwards the MAC PDUs to the LCH-ID de-multiplexing entity 712. TheLCH-ID de-multiplexing entity 712 routes the MAC-ehs SDUs to correctlogical channel based on the received logical channel identifier.

The disassembly entity 704 may perform additional processing to extractthe reordering PDUs addressed to the WTRU and discard the rest of thereordering PDUs, and then deliver the reordering PDUs addressed to theWTRU to the reordering distribution entity. The additional processingperformed by the disassembly entity may depend on the type of MAC-ehsformat.

In case of a continuous MAC-ehs header as shown in FIG. 3, thedisassembly entity 704 may find the WTRU address in the MAC-ehs headerbefore extracting the MAC-ehs payload for this particular WTRU. In casewhere a MAC-ehs header is added before each MAC-ehs payload as shown inFIG. 4, the disassembly entity 704 may find the MAC-ehs header includingits WTRU address before removing the headers, the padding bits and thereordering PDUs not addressed to this WTRU before delivering thereordering PDUs addressed to this WTRU to the reordering distributionentity. In case no change to the MAC-ehs header has been implemented,the disassembly entity 704 may use the de-multiplexing informationprovided by layer 1 and/or implicit rules before extracting thereordering PDUs addressed to the WTRU. De-multiplexing information mayinclude number of WTRUs multiplexed, length of each MAC-ehs payload,etc.

FIG. 8 shows an example MAC-ehs entity on the WTRU side supportingMAC-ehs PDU multiplexing in case individual WTRU MAC-ehs PDUs aremultiplexed into a final MAC-ehs PDU. The MAC-ehs PDU de-multiplexingentity 703 is introduced to de-multiplex the individual WTRU MAC-ehsPDUs and forward its own data to the disassembly entity 704. The MAC-ehsPDU de-multiplexing entity 703 may use the WTRU ID or index to determinewhich individual WTRU MAC-ehs PDU belongs to the WTRU, and forward it tothe disassembly entity 704. The MAC-ehs PDU de-multiplexing entity 703may discard the MAC-ehs PDU(s) that do not belong to this WTRU.

It should be noted that the functionality of the MAC-ehs PDUde-multiplexing entity may be included in the disassembly entity.

FIG. 9 is an example MAC-ehs entity on the UTRAN side supporting WTRUmultiplexing in one embodiment. The scheduling/priority handling entity902 manages HS-DSCH resources between HARQ entities and data flowsaccording to their priority class. The priority queue distributionentity 904 distributes received MAC-ehs SDUs to priority queues 906. Thesegmentation entity 908 performs necessary segmentation of MAC-ehs SDUs.The priority queue MUX entity 910 determinates the number of octets tobe included in a MAC-ehs PDU from each priority queue based on thescheduling decision and available TFRC for this function. The HARQentity 914 handles the HARQ functionalities. The TFRC selection entity916 performs the TFRC selection for MAC-ehs.

In order to allow the network to multiplex a number of WTRUs in anMAC-ehs transport block, a new entity called “WTRUs multiplexing entity”912 may be introduced, (e.g., between the scheduling/priority handlingentity 902 and the HARQ entity 914). For each WTRU there may be onescheduling/priority handling entity 902, (e.g., priority queuedistribution, segmentation, and priority queue mux), however, there maybe one WTRUs multiplexing entity 912. Alternatively, there may be onescheduling/priority handling entity 902 for a group of WTRUs that may bemultiplexed together.

The WTRUs multiplexing entity 912 determines the number of WTRUs andamount of data that may be included in the (final) MAC-ehs PDU. TheWTRUs multiplexing entity may multiplex the MAC-ehs PDUs created foreach WTRU in the scheduling/priority handling entity 902 and deliver the(final) MAC-ehs PDU to the HARQ entity 914. Alternatively, the WTRUsmultiplexing entity 912 may multiplex reordering PDUs of multiple WTRUsin one MAC-ehs PDU by using one of the formats disclosed above.

The priority queue MUX entity 910 may be bypassed and the WTRUsmultiplexing entity 912 may have the functionality of determining thenumber of bytes to be included in an MAC-ehs PDU from each priorityqueue and from each WTRU. Embodiments for HARQ operations formultiplexing of WTRUs in a same transport block are described below.

In one embodiment, WTRUs multiplexed in the transport block may sendback a positive acknowledgement (ACK) or a negative acknowledgement(NACK). When a Node-B receives a NACK from one or multiple WTRUs forwhich the data has been multiplexed, the Node-B may retransmit the sametransport block to the group of WTRUs as it was sent before so that theWTRUs may perform soft combining.

Alternatively, the Node-B may transmit a new transport block which maycontain the MAC-ehs payloads of the WTRUs of the group which sent aNACK, excluding the data of the WTRUs which sent an ACK. For example, incase data for three WTRUs were multiplexed and if UE1 and UE3 sent backa NACK while UE2 sent back an ACK, the Node-B may send a new transportblock containing the data for UE1 and UE3.

Alternatively, the Node-B may transmit a new transport block which maycontain new MAC-ehs payload in addition to the negatively acknowledgedMAC-ehs payload of the WTRUs. For example, if data to UE1 and UE2 weremultiplexed in the initial transmission, and UE1 sent a NACK while UE2sent an ACK, the Node-B may send a new transport block including thenegatively acknowledged data for UE1 and new data for any other WTRU.

In another embodiment, the WTRUs which received multiplexed data may notsend any ACK or NACK to the network, and the Node-B may transmit thesame transport block for a predetermined number of times to the WTRUs.The WTRUs may use the new data indicator or the physical layerredundancy version coding to find out if it is a new transmission or aretransmission. In case of a retransmission, the WTRU may combine thedata with the data previously received.

In case the WTRU is configured for HS-SCCH-less operation, the CRC ofthe HS-DSCH may be partially masked with the group WTRU identityassigned to the WTRUs for which the data is multiplexed. When the layer1on the WTRU side decodes successfully the HS-DSCH, the WTRU may decodethe group WTRU identity by using the CRC, and find out if the data isaddressed to the WTRU.

In current HSDPA, multiple WTRUs may be scheduled within a single 2 msTTI using code division multiplexing (CDM), as shown in FIG. 10. Tomitigate the inter-code interference among code-multiplexed MIMO-capable WTRUs, time division multiplexing (TDM) of the WTRUs within one TTImay be used. In that case, the Node B scheduler allocates an individualtimeslot within a TTI to a user, as shown in FIG. 11.

Hereafter, the terminology “TDM mode” is used to describe a mode ofoperation where transmissions destined to multiple WTRUs aretime-multiplexed within a TTI. While embodiments may be described in thecontext of a slotwise time-multiplexing, (that is each WTRU is assignedto a single radio slot), other time-multiplexing approaches may beapplicable. In one example of such time-multiplexing approach may betransmitting the data symbols from multiple WTRUs in time-alternation.In the following description, the term “time-multiplexing slot” refersto the set of symbols in a TTI dedicated to a single WTRU.

Embodiments for switching between the legacy mode and a TDM mode andactivating and deactivating the TDM mode are disclosed hereafter. TheTDM mode may be configured and operated in a static or semi-static way,or alternatively in a dynamic way. When TDM mode is configured andenabled, the WTRU operates with the knowledge that any HS-PDSCH receivedmay carry data for more than one WTRU in a time-division manner. Instatic or semi-static configuration, the WTRU may be configured tooperate in a TDM mode for several consecutive subframes, whereas indynamic configuration, the WTRU is indicated on a subframe-by-subframebasis whether or not the transmission is using a TDM mode.

The TDM mode may be a semi-static parameter signalled via a high layer.A new information element (IE) for the TDM mode configuration may beincluded in an RRC message. An RNC may send this message to the WTRU,and the WTRU extracts the TDM MIMO mode configuration information fromthis RRC message. Alternatively, layer 2 signals may be used for theconfiguration of the TDM mode, (e.g., MAC header). Upon reception ofthis parameter, the WTRU may apply the TDM mode configuration. Whenconfigured in a TDM mode, transmissions to the WTRU may be sent in a TDMmode.

In another embodiment, the TDM mode may be activated and deactivateddynamically via lower-layer signalling.

In one embodiment, the TDM mode may be activated and deactivated viaout-of-band signalling. The out-of-band signalling may be implementedusing an HS-SCCH order. Table 1 shows an example implementation of theHS-SCCH order mapping when the order type is “000.” A new order type maybe introduced for the TDM activation and deactivation.

TABLE 1 Order bits X_(ord,1) = X_(ord,2) = X_(ord,3) = Order typeX_(drx,1) X_(dtx,1) X_(hs-scch-less,1) Order 000 0 0 0 DRX, DTX,HS-SCCH-less deactivation 0 0 1 DRX, DTX deactivation HS-SCCH-lessactivation 0 1 0 DRX, HS-SCCH-less deactivation, DTX activation 0 1 1DRX deactivation, DTX, HS-SCCH-less activation 1 1 0 DRX, DTXactivation, HS-SCCH-less deactivation 1 1 1 DRX, DTX, HS-SCCH-lessactivation 1 0 0 TDM deactivation 1 0 1 TDM activation

Upon reception of the TDM activation order, subsequent transmissions tothe WTRU may be sent in a TDM mode (e.g., until a deactivation order isreceived or an RRC configuration message disabling the TDM mode isreceived). Alternatively, the TDM mode may be further indicateddynamically via in-band signalling.

In another embodiment, the TDM mode indication may be carried by thein-band signalling over an HS-SCCH so that the TDM mode may bedynamically switched on TTI-wise or slot wise. The HS-SCCH may be of thetype for non-MIMO, (e.g., HS-SCCH type 1), or of the type for MIMO,(e.g., HS-SCCH type 3).

The TDM mode indication may be set based on the HS-SCCH number.Conventionally, seven channelization code set bits of the HS-SCCH(x_(ccs,1), x_(ccs,2), . . . , x_(ccs,7)) are set for assigning achannelization code set for a WTRU. Given P (multi-)codes starting atcode O, and given the HS-SCCH number, the information-field iscalculated using the unsigned binary representation of integerscalculated by the expressions below. For the first three bits (codegroup indicator) of which x_(ccs,1) is the MSB:

x _(ccs,1) ,x _(ccs,2) ,x _(ccs,3)=min(P−1,15-P).

For HS-SCCH type 1, if 64QAM is not configured for the WTRU, or if 64QAMis configured and x_(ms,1)=0, then P and O may fulfill the following:

|O−1-└P/8┘*15|mod 2=(HS-SCCH number)mod 2,

and for the last four bits (code offset indicator) of which x_(ccs,4) isthe MSB, and then

x _(ccs,4) ,x _(ccs,5) ,x _(ccs,6) ,x _(ccs,dummy) =|O−1-└P/8┘*15|,

where x_(ccs,dummy) is a dummy bit that is not transmitted on HS-SCCH.x_(ccs,7) may be set as follows:

$x_{{ccs},7} = \left\{ {\begin{matrix}0 & {{if}\mspace{14mu} {Normal}\mspace{14mu} {mode}} \\1 & {{if}\mspace{14mu} {TDM}\mspace{14mu} {mode}}\end{matrix}.} \right.$

If 64QAM is configured for the WTRU and x_(ms,1)=1, P and O may fulfillthe following:

|O−1-└P/8┘*15|mod 4=(HS-SCCH number)mod 4, and

x _(ccs,4) ,x _(ccs,5) ,x _(ccs,dummy1) ,x _(ccs,dummy2)=|O−1-└P/8┘*15|,

where x_(ccs,dummy1), x_(ccs,dummy2) are two dummy bits that are nottransmitted on HS-SCCH. x_(ccs,6) and x_(ccs,7) may be set as follows:

$x_{{ccs},6} = \left\{ {\begin{matrix}0 & {{if}\mspace{14mu} {Normal}\mspace{14mu} {mode}} \\1 & {{if}\mspace{14mu} {TDM}\mspace{14mu} {mode}}\end{matrix},{{{and}x_{{ccs},7}} = \left\{ {\begin{matrix}0 & {{if}\mspace{14mu} 16{QAM}} \\1 & {{if}\mspace{14mu} 64{QAM}}\end{matrix}.} \right.}} \right.$

For HS-SCCH type 3, if 64QAM is not configured for the WTRU, or if 64QAMis configured and x_(ms,1), x_(ms,2), x_(ms,3) is not equal to “101”, Pand O may fulfill the following:

|-1-└P/8┘*15|mod 2=(HS-SCCH number)mod 2, and

for the last four bits (code offset indicator) of which Xccs,4 is theMSB

x _(ccs,4) ,x _(ccs,5) ,x _(ccs,6) ,x _(ccs,dummy) =|O−1-└P/8┘*15|,

where x_(ccs,dummy) is a dummy bit that is not transmitted on HS-SCCH.x_(ccs,7) may be set as follows:

$x_{{ccs},7} = \left\{ {\begin{matrix}0 & {{if}\mspace{14mu} {Normal}\mspace{14mu} {mode}} \\1 & {{if}\mspace{14mu} {TDM}\mspace{14mu} {mode}}\end{matrix}.} \right.$

If 64QAM is configured for the WTRU and x_(ms,1), x_(ms,2), x_(ms,3) isequal to “101”, P and O may fulfill the following:

|O−1-└P/8┘*15|mod 4=(HS-SCCH number)mod 4, and

x _(ccs,4) ,x _(ccs,5) ,x _(ccs,dummy1) ,x _(ccs,dummy2)=|O−1-└P/8┘*15|,

where x_(ccs,dummy1), x_(ccs,dummy2) are two dummy bits that are nottransmitted on HS-SCCH. x_(ccs,6) and x_(ccs,7) may be set as follows:

$x_{{ccs},6} = \left\{ {\begin{matrix}0 & {{if}\mspace{14mu} {Normal}\mspace{14mu} {mode}} \\1 & {{if}\mspace{14mu} {TDM}\mspace{14mu} {mode}}\end{matrix},} \right.$

x_(ccs,7)=0 if the modulation for the secondary transport block is QPSK,and

x_(ccs,7)=1 if the number of transport blocks=1.

It should be noted that the in-band and out-band signalling are notmutually exclusive. For example, when the TDM is activated byout-of-band signalling (e.g., HS-SCCH order), in-band signalling maystill be used to enable and disable the TDM mode on a slot-basis.

Embodiments for signalling downlink control information to WTRUs thatare multiplexed within a single TTI are discloses hereafter.

A dedicated HS-SCCH may be transmitted to each WTRU having an allocationin the corresponding TTI.

In one embodiment, a Node B may send the conventional HS-SCCH to eachWTRU and the timeslot(s) or time-multiplexing slot carrying itsassociated data to each WTRU, (e.g., on the HS-PDSCH), within a TTI maybe signaled either implicitly or explicitly.

Embodiments for implicit indication of the time slot are disclosedhereafter. The HS-SCCH number may be used to indicate the slotallocation within one TTI. For example in the case where 3time-multiplexing slots are configured, if (HS-SCCH number) mod 3=0, itmay indicate that the WTRU is assigned to slot 1, if (HS-SCCH number)mod 3=1, it may indicate that the WTRU is assigned to slot 2, if(HS-SCCH number) mod 3=2, it may indicate that the WTRU is assigned toslot 3.

Alternatively, the cyclic redundancy check (CRC) of the transport blockcarried on the HS-PDSCH may be masked with the WTRU H-RNTI. When a WTRUdetects an H-RNTI on the HS-SCCH, the WTRU attempts to decode a specifictime-multiplexing slot and uses its own H-RNTI for CRC decoding toidentify which time-multiplexing slot was intended to this WTRU.

Alternatively, each TDM-capable WTRU may be assigned with multipleH-RNTIs and one of them may be used for each WTRU at a time, and eachH-RNTI may be associated with a particular time-multiplexing slot. Forexample, if a WTRU is assigned with three H-RNTIs, (H-RNTI1, H-RNTI2,and H-RNTI3), and if H-RNTI2 is decoded in the HS-SCCH, the WTRU maydetermine that the associated data is transmitted, (e.g., on theHS-PDSCH), over the second slot.

Alternatively, time-multiplexing slot allocation may be indicated basedon the single WTRU ID or H-RNTI. Each WTRU may be assigned with oneunique H-RNTI. For example, if (WTRU ID) mod 3=0, it may indicate thatthe WTRU is assigned to the first time-multiplexing slot of the TTI, if(WTRU ID) mod 3=1, it may indicate that the WTRU is assigned to thesecond time-multiplexing slot of the TTI, and if (WTRU ID) mod 3=2, itmay indicate that the WTRU is assigned to the third time-multiplexingslot of the TTI.

Embodiments for explicit indication of the time-multiplexing slot aredisclosed hereafter. The HS-SCCH type 1 and 3 may be used to signal thetime-multiplexing slot allocation. For example, the channelization codeset bits x_(ccs,4), x_(ccs,5), . . . , x_(ccs,7) may be coded as follows(the first three bits x_(ccs,1), x_(ccs,2), x_(ccs,3) may be coded usingthe conventional method.

For HS-SCCH type 1, if 64QAM is not configured for the WTRU, or if 64QAMis configured and x_(ms,1)=0, P and O may fulfill the following:

|O−1-└P/8┘*15|mod 4=(HS-SCCH number)mod 4, and

for the last four bits (code offset indicator) of which x_(ccs,4) is theMSB,

x _(ccs,4) ,x _(ccs,5) ,x _(ccs,dummy1) ,x _(ccs,dummy2)=|O−1-└P/8┘*15|,

where x_(ccs,dummy1), x_(ccs,dummy2) are two dummy bits that are nottransmitted on HS-SCCH. x_(ccs,6) and x_(ccs,7) may be set as follows:

${x_{{ccs},6}x_{{ccs},7}} = \left\{ {\begin{matrix}00 & {{if}\mspace{14mu} {slot}\mspace{14mu} 1\mspace{14mu} {is}\mspace{14mu} {assigned}} \\01 & {{if}\mspace{14mu} {slot}\mspace{14mu} 2\mspace{14mu} {is}\mspace{14mu} {assigned}} \\10 & {{if}\mspace{14mu} {slot}\mspace{14mu} 3\mspace{14mu} {is}\mspace{14mu} {assigned}} \\11 & {{not}\mspace{14mu} {used}}\end{matrix}.} \right.$

If 64QAM is configured for the WTRU and x_(ms,1)=1, P and O may fulfillthe following:

|O−1-└P/8┘*15|mod 4=(HS-SCCH number)mod 4, and

x _(ccs,4) ,x _(ccs,5) ,x _(ccs,dummy1) ,x _(ccs,dummy2)=|O−1-└P/8┘*15|,

where x_(ccs,dummy1), x_(ccs,dummy2) are two dummy bits that are nottransmitted on HS-SCCH. x_(ccs,6) and x_(ccs,7) may be set as follows:

$x_{{ccs},6} = \left\{ {\begin{matrix}0 & {{if}\mspace{14mu} {slot}\mspace{14mu} 1\mspace{14mu} {is}\mspace{14mu} {assigned}} \\1 & {{if}\mspace{14mu} {slot}\mspace{14mu} 2\mspace{14mu} {is}\mspace{14mu} {assigned}}\end{matrix},{{{and}x_{{ccs},7}} = \left\{ {\begin{matrix}0 & {{if}\mspace{14mu} 16{QAM}} \\1 & {{if}\mspace{14mu} 64{QAM}}\end{matrix}.} \right.}} \right.$

For HS-SCCH type 3, if 64QAM is not configured for the WTRU, or if 64QAMis configured and x_(ms,1), x_(ms,2), x_(ms,3) is not equal to “101”, Pand O may fulfill the following:

|O−1-└P/8┘*15|mod 4=(HS-SCCH number)mod 4, and

for the last four bits (code offset indicator) of which x_(ccs,4) is theMSB

x _(ccs,4) ,x _(ccs,5) ,x _(ccs,dummy1) ,x _(ccs,dummy) =|O−1-└P/8┘*15|,

where x_(ccs,dummy1), x_(ccs,dummy2) are two dummy bits that are nottransmitted on HS-SCCH. x_(ccs,6) and x_(ccs,7) may be set as follows:

${x_{{ccs},6}x_{{ccs},7}} = \left\{ \begin{matrix}00 & {{if}\mspace{14mu} {slot}\mspace{14mu} 1\mspace{14mu} {is}\mspace{14mu} {assigned}} \\01 & {{if}\mspace{14mu} {slot}\mspace{14mu} 2\mspace{14mu} {is}\mspace{14mu} {assigned}} \\10 & {{if}\mspace{14mu} {slot}\mspace{14mu} 3\mspace{14mu} {is}\mspace{14mu} {assigned}} \\11 & {{not}\mspace{14mu} {used}}\end{matrix} \right.$

If 64QAM is configured for the WTRU and x_(ms,1), x_(ms,2), x_(ms,3) isequal to “101”, P and O may fulfill the following:

|O−1-└P/8┘*15|mod 4=(HS-SCCH number)mod 4, and

x _(ccs,4) ,x _(ccs,5) ,x _(ccs,dummy1) ,x _(ccs,dummy2)=|O−1-└P/8┘*15|,

where x_(ccs,dummy1), x_(ccs,dummy2) are two dummy bits that are nottransmitted on HS-SCCH. x_(ccs,6) and x_(ccs,7) may be set as follows:

$x_{{ccs},6} = \left\{ {\begin{matrix}0 & {{if}\mspace{14mu} {slot}\mspace{14mu} 2\mspace{14mu} {is}\mspace{14mu} {assigned}} \\1 & {{if}\mspace{14mu} {slot}\mspace{14mu} 3\mspace{14mu} {is}\mspace{14mu} {assigned}}\end{matrix},} \right.$

and

x_(ccs,7)=0 if the modulation for the secondary transport block is QPSK,and

x_(ccs,7)=1 if the number of transport blocks=1.

In another embodiment, a new HS-SCCH format may be defined to occupy onetime-multiplexing slot so that three HS-SCCHs may be time multiplexedinto one 2 ms TTI and share the same channelization code. FIG. 12 showsexample slot-wise HS-SCCH signaling scheme and timing relationshipbetween HS-SCCH and HS-PDSCH. Similar to the conventional HS-SCCHs,HS-SCCH type 1 applies to non-MIMO WTRUs in TDM mode while HS-SCCH type3 applies to MIMO WTRUs in TDM mode, or a Node B may use HS-SCCH type 3as downlink signalling for both non-MIMO WTRUs and MIMO WTRUs.

FIG. 13 is an example flow diagram of HS-SCCH encoding for a non-MIMOmode, (i.e., new HS-SCCH format that fits one time slot). The redundancyversion (RV) parameters r, s and constellation version parameter b arecoded jointly to produce the value X_(rv) (1302). The channelizationcode set information x_(ccs), modulation scheme information x_(ms),transport block size information x_(tbs), HARQ process informationx_(hap), redundancy and constellation version x_(rv) new data indicatorx_(nd) are multiplexed into a sequence X (1304). Channel coding and ratematching are performed on the sequence X (1306, 1308). WTRU-specificscrambling, (e.g., all or part of the sequence X is XORed with the WTRUidentity (X_(WTRU)) bits or a sequence derived from the WTRU identity),is performed with WTRU identity x_(ue) (1310), before mapping to HS-SCCHphysical channel (1312). Either all or partial control information maybe coded and transmitted. At the WTRU receiver, by de-scrambling thereceived HS-SCCH using its own WTRU ID, the WTRU may determine if theHS-DSCH transmission was intended for it or not. As there is no CRC inthe coding for HS-SCCH, the transport block CRC may be masked orscrambled with the WTRU ID.

FIG. 14 is an example flow diagram of HS-SCCH encoding for an MIMO mode,(i.e., new HS-SCCH format that fits one time slot). For each of theprimary transport block and a secondary transport block if two transportblocks are transmitted on the associated HS-PDSCH(s), the RV parametersr, s and constellation version parameter b are coded jointly to producethe values X_(rvpb) and X_(rvsb), respectively (1402). Channelizationcode set information x_(ccs), modulation scheme and number of transportblocks information x_(ms), precoding weight information for the primarytransport block x_(pwipb), transport block size information for theprimary transport block X_(tbspb), transport block size information forthe secondary transport block X_(tbssb), HARQ process informationx_(hap), redundancy and constellation version for the primary andsecondary transport blocks x_(rvpb), x_(rvsb) are multiplexed into asequence X (1404). Channel coding and rate matching are performed on thesequence X (1406, 1408). WTRU-specific scrambling is performed with WTRUidentity x_(WTRU) (1410), before mapping to HS-SCCH physical channel(1412). Either all or partial control information may be coded andtransmitted. At the WTRU receiver, by de-scrambling the received HS-SCCHusing its own WTRU ID, the WTRU may determine if the HS-DSCHtransmission was intended for it or not. As there is no CRC in thecoding for HS-SCCH, the transport block CRC may be masked or scrambledwith the WTRU ID.

FIGS. 15 and 16 are other example flow diagrams of HS-SCCH encoding fora non-MIMO mode and an MIMO mode, respectively, (i.e., new HS-SCCHformat that fits one time slot). In these examples, instead ofperforming WTRU-specific scrambling on the sequence X (1310, 1410) asshown in FIGS. 13 and 14, a CRC is generated from the sequence X andWTRU-specific CRC attachment may be performed with the CRC bits (e.g.,all or part of the CRC bits are XORed with the WTRU identity (X_(WTRU))bits or a sequence derived from the WTRU identity) (1506, 1606). Eitherall or partial control information may be coded and transmitted.

In another embodiment, some of the control information in part 1 of theHS-SCCH may not be signaled and the unused field(s) may be reinterpretedto reduce the required information bits. For example, code group ornumber of codes P may be signaled and code offset O may be common to TDMWTRUs or may be signaled by higher layers, and the bits for O may bereinterpreted. Alternatively, neither P nor O may be signaled and TDMWTRUs may use the same set of codes, (e.g., all 15 codes), and bits forP and O may be reinterpreted. Alternatively, a subset of thechannelization codes may be allowed and bits for P and O may bereinterpreted. Alternatively, fixed modulation scheme or a subset of themodulation schemes may be allowed and bits for modulation scheme may bereinterpreted. Alternatively, a subset of the transport block sizes maybe allowed and bits for transport block size may be reinterpreted. ForMIMO-capable WTRUs, dual or multiple stream transmission may not beallowed.

In another embodiment, the spreading factor of the HS-SCCH may bereduced to 128/N, where N denotes the maximum number of WTRUs whoseHS-PDSCH time multiplexed into one 2 ms TTI, which can be any integernumber of power of 2. In this embodiment, N HS-SCCHs may be timemultiplexed into one 2 ms TTI. N HS-SCCHs may be share the samechannelization code or use the different channelization codes. Thisallows multiple HS-SCCHs for different WTRUs transmitted in a TDMfashion.

In another embodiment, a joint HS-SCCH format for time multiplexed WTRUsmay be defined which occupies one 2 ms TTI. A joint HS-SCCH format mayinclude a common part and a plurality of WTRU-specific parts. Each ofthe WTRU-specific parts may include CRC masked with each WTRU H-RNTI.The common part may include the common control information that isshared for TDM WTRUs while the WTRU-specific parts include theWTRU-specific control information for each WTRU.

The common part may include at least one of the following:channelization code set information, modulation scheme information, HARQprocess information, redundancy and constellation version, new dataindicator, WTRU identity, transport block size information, precodingweight information if one transport block is configured for MIMO mode),number of transport blocks information if one transport block isconfigured for MIMO mode), precoding weight information for the primarytransport block if two transport blocks are configured for MIMO mode),transport block size information for the primary transport block if twotransport blocks are configured for MIMO mode), transport block sizeinformation for the secondary transport block if two transport blocksare configured for MIMO mode), redundancy and constellation version forthe primary transport block if two transport blocks are configured forMIMO mode), redundancy and constellation version for the secondarytransport block if two transport blocks are configured for MIMO mode),etc. The information that is not included in the common part may besignaled via the WTRU-specific parts.

Any parameter included in the common part may not be included in theWTRU-specific parts, and vice versa. The common part may include thecontrol information shared for the TDM WTRUs as much as possible suchthat the least control information may be included in individualWTRU-specific parts. Alternatively, the common part may include limitedcommon control information shared for the TDM WTRUs such that the morecontrol information may be included in each of the WTRU-specific parts.Alternatively, the joint HS-SCCHs may be scheduled based on the tradeoffof scheduling flexibility and signaling overhead reduction.

Embodiments for addressing the common part and WTRU-specific parts aredisclosed hereafter. In one embodiment, the common part may not bemasked with a WTRU ID, and each of the WTRU-specific parts may be maskedwith a corresponding WTRU identity, (e.g., CRC masking with an H-RNTI).In this case, any WTRUs within a cell may decode the common part, andeach WTRU determines which one of the WTRU-specific parts is addressedto itself based on the WTRU-specific masking on the WTRU-specific parts.

In another embodiment, the common part may be masked with a group WTRUidentity, (e.g., a group H-RNTI), and each of the WTRU-specific partsmay be masked with a corresponding WTRU identity, (e.g., CRC maskingwith an H-RNTI). A group WTRU identity may be assigned to several WTRUsby a high layer, (e.g., via an RRC configuration or reconfigurationmessage), or by the layer 1 signaling, (e.g., an HS-SCCH order). Thegroup WTRU identity may be applied to the common part of the jointHS-SCCH, (i.e., WTRU-specific scrambling), to indicate which WTRUs thecontrol information is addressed to. The WTRUs belonging to this groupmay decode the common part to obtain the control information by usingthe group WTRU identity, and then each WTRU detects which one of theWTRU-specific parts is addressed to itself by using its own H-RNTI.

FIG. 17 shows an example encoding chain of the joint HS-SCCH for anon-MIMO mode. In this example, the channelization code set informationx_(ccs), and the modulation scheme information x_(ms) are the commonpart. The channelization code set information x_(ccs), modulation schemeinformation x_(ms) are multiplexed (1702) and group H-RNTI masking,(e.g., all or part of the common part is XORed with the WTRU identity(X_(WTRU)) bits or a sequence derived from the WTRU identity), may beperformed (1704) before channel coding and rate matching (1706, 1708).Alternatively, as disclosed above, the group H-RNTI masking (1704) maynot be performed on the common part. For each WTRU, the RV parameters r,s and constellation version parameter b are coded jointly to produce thevalue X_(rv) ((1710), and transport block size information x_(tbs), HARQprocess information x_(hap), redundancy and constellation version x_(rv)and new data indicator x_(nd) are multiplexed (1712), and WTRU-specificCRC attachment is performed, (all or part of the CRC bits generated fromeach WTRU-specific part is XORed with the corresponding WTRU identity(X_(WTRU)) bits or a sequence derived from the WTRU identity) (1714).The WTRU-specific parts are then multiplexed (1716) and channel codingand rate matching are performed (1718, 1720). The common part and theWTRU-specific parts are combined and physical channel mapping isperformed (1722). Alternatively, WTRU-specific CRC may be attached tothe common part and WTRU-specific scrambling may be performed to theWTRU-specific parts.

FIG. 18 shows an example encoding chain of the joint HS-SCCH for an MIMOmode. In this example, channelization code set information x_(ccs),modulation scheme and number of transport blocks information x_(ms), andprecoding weight information for the primary transport block x_(pwipb)are the common part. The common part information is multiplexed (1802),and group H-RNTI masking, (e.g., all or part of the common part is XORedwith the WTRU identity (X_(WTRU)) bits or a sequence derived from theWTRU identity), may be performed (1804), and channel coding and ratematching are performed (1806, 1808). Alternatively, as disclosed above,the group H-RNTI masking (1804) may not be performed on the common part.For each WTRU, the RV parameters r, s and constellation versionparameter b are coded jointly to produce the value X_(rvpb) and X_(rvsb)((1810), transport block size information for the primary transportblock x_(tbspb), transport block size information for the secondarytransport block x_(tbssb), HARQ process information x_(hap), redundancyand constellation version for the primary and secondary transport blocksx_(rvpb), x_(rvsb) are multiplexed (1812), and WTRU-specific CRCattachment may be performed, (all or part of the CRC bits generated fromeach WTRU-specific part is XORed with the corresponding WTRU identity(X_(WTRU)) bits or a sequence derived from the WTRU identity) (1814).The WTRU-specific parts are then multiplexed (1816) and channel codingand rate matching are performed (1818, 1820). The common part and theWTRU-specific parts are combined and physical channel mapping isperformed (1822). Alternatively, WTRU-specific CRC may be attached tothe common part and WTRU-specific scrambling may be performed to theWTRU-specific parts.

Upon reception of the HS-SCCH, the WTRU applies the reverse operation toobtain the common and WTRU-specific information. More specifically, theWTRU receives the common part of the HS-SCCH and may apply the groupidentity mask to determine whether or not the HS-SCCH belongs to itsgroup. If the WTRU determines that the HS-SCCH is directed to its group,the WTRU then may decode the second part (WTRU-specific parts) of theHS-SCCH and attempt decoding each of the WTRU-specific parts with itsown H-RNTI or WTRU-specific CRC mask. If the WTRU determines that one ofthe WTRU-specific parts is directed to itself based on WTRU-specific CRCor WTRU-specific scrambling, the WTRU attempts to decode the associatedHS-PDSCH transmission using the HS-SCCH common and WTRU-specificinformation.

WTRUs report channel quality indication (CQI) to the Node B to provideinformation to be used in scheduling and network performanceoptimization. The introduction of TDM may introduce changes (dependingon scheduler behaviour) in the interference environment seen by the WTRUon a time-multiplexing slot basis.

The WTRUs may report a CQI feedback on a slot basis. The WTRUs mayreport a CQI based on multiple slots measurements for the sametime-multiplexing slot position in a group of TTI, as the WTRU may seesimilar interference for each time-multiplexing slot location in the TTIon a TTI by TTI basis. In the following the term slot may alsoequivalently refer to a time-multiplexing slot.

In one embodiment, 1-slot reference period may be introduced for the CQIfor TDM WTRU for both non-MIMO and MIMO cases. When the WTRU is notconfigured in an MIMO mode, based on an unrestricted observationinterval, the WTRU may report the highest tabulated CQI value for whicha single HS-DSCH sub-frame formatted with the transport block size,number of HS-PDSCH codes and modulation corresponding to the reported orlower CQI value may be received with a transport block error probabilitynot exceeding 0.1 in a 1-slot reference period ending at least 1 slotbefore the start of the first slot in which the reported CQI value istransmitted (assuming the legacy HS-DPCCH structure is maintained).

When the WTRU is configured in an MIMO mode, based on an unrestrictedobservation interval, the WTRU may report the highest tabulated CQIvalue(s) for which a single HS-DSCH sub-frame formatted with the set oftransport block size(s), number of HS-PDSCH codes and set ofmodulation(s) corresponding to the reported CQI value(s) may be receivedwith individual transport block error probabilities not exceeding 0.1 ina 1-slot reference period ending at least 1 slot before the start of thefirst slot in which the reported CQI value(s) is/are transmitted(assuming the legacy HS-DPCCH structure is maintained) if the preferredprimary precoding vector as indicated by the PCI value reported in thesame HS-DPCCH sub-frame may be applied at the Node B for the primarytransport block and in case two transport blocks are preferred theprecoding vector orthogonal to the preferred primary precoding vectormay be applied for the secondary transport block.

A CQI may be reported and the Node B may adjust the transport block sizeto meet the 1 slot performance.

Alternatively, a CQI may be reported based on transport block size thatmay be supported in 1-slot, measured over an undefined number ofprevious slots.

Alternatively, a CQI may be reported based on the transport block sizethat may be supported in 1-slot, measured during like slots, (e.g., thefirst slot in each TTI), over an undefined number of slots. The slot tobe reported on may be defined by the network, (e.g., Node B or RNC).Alternatively, the slot to be reported on may be chosen by the WTRU. TheWTRU may choose the best (or alternatively the worst or median)performing slot. The WTRU may indicate which slot is chosen, by thetiming of the CQI report, (e.g., if slot 1 is chosen then the WTRU maytransmit the report in the third slot, if slot 2 is chosen the WTRU maytransmit the report in the first slot, and if slot 3 is chosen the WTRUmay transmit the report in the second slot).

Alternatively, a WTRU may report a CQI for the transport block size thatmay be supported in 1-slot for each of the slots in a TTI, (e.g.,1^(st), 2^(nd), 3^(rd)). A WTRU may report three CQI reports, whereineach CQI is generated based on measurements during like slots, (e.g.,the first slot in the TTI for the first slot report, and so on).

The CQI reported for each of the slots may be sent in an order, (e.g.,the first slot report, the second slot report, and the third slotreport).

Alternatively, the CQI may be reported for each of the slots in a singleCQI report. This may require a new CQI table which allows for thereporting of the multiple CQI reports. One report may provide anindependent CQI report for each slot, (e.g., for the three slots of theTTI).

Alternatively, the CQI may be reported for each of the slots in a singleCQI report as a CQI value for one of the slots, and differential valuesfor the other slots. The slot to be reported and used as the basis forthe differential reporting may be defined by the network, or chosen bythe WTRU, (e.g., the WTRU may choose the best performing slot and thenreport the differential values for the other slots). The choice may besignaled by the location of the CQI report, (e.g., if slot 1 is chosenthen it may be transmitted in the third slot, if slot 2 is chosen it maybe transmitted in the first slot, and if slot 3 is chosen it may betransmitted in the second slot.) Alternatively, the choice may besignaled in the CQI report.

New WTRU categories may be introduced to indicate the WTRU capability tosupport TDM mode. The WTRU may signal the TDM mode capability to thenetwork through an RRC message. For the new WTRU categories and/or moreaccurate measurements, a new CQI table may be defined with biggergranularity. Alternatively, part of the conventional CQI table may bereused, (e.g., the new table has the biggest entries which are less than1/N of the original biggest CQI value). Alternatively, based on multipleindividual single slot CQI measurements, a single CQI value may becalculated and listed in the new CQI table.

Embodiments

1. A method for multiplexing data for multiple WTRUs for high speeddownlink channels in a TTI.

2. The method of embodiment 1 comprising receiving a joint HS-SCCH, thejoint HS-SCCH including a common part and WTRU-specific parts.

3. The method of embodiment 2 wherein the common part includes commoncontrol information for WTRUs multiplexed in one TTI, and each of theWTRU-specific parts includes WTRU-specific control information for acorresponding WTRU.

4. The method as in any one of embodiments 2-3, comprising receiving anHS-PDSCH based on decoding on the joint HS-SCCH.

5. The method as in any one of embodiments 2-4, wherein each of theWTRU-specific parts include CRC bits masked with a corresponding WTRUidentity.

6. The method as in any one of embodiments 2-5, wherein all or part ofeach of the WTRU-specific parts is masked with a WTRU identity bits or abit sequence derived from the WTRU identity.

7. The method as in any one of embodiments, 2-6, wherein the commoncontrol information is not masked with any identity.

8. The method as in any one of embodiments 2-7, wherein all or a part ofthe common control information on the common part is masked with groupWTRU identity bits or a bit sequence derived from a group WTRU identity.

9. The method as in any one of embodiments 2-8, further comprisingdetermining whether the common part of the joint HS-SCCH is directed tothe WTRU based on a group identity.

10. The method of embodiment 9 comprising determining whether any one ofthe WTRU-specific parts of the joint HS-SCCH is directed to the WTRUbased on a WTRU-specific identity.

11. The method of embodiment 10 comprising decoding the HS-PDSCH usingthe common control information and the WTRU-specific control informationfor the WTRU.

12. A method for multiplexing data for multiple WTRUs for high speeddownlink channels in a TTI.

13. The method of embodiment 12 comprising receiving an HS-SCCH, theHS-SCCH including a group WTRU identity shared by a group of WTRUs.

14. The method of embodiment 13 comprising receiving an HS-PDSCH basedon decoding on the HS-SCCH with the group WTRU identity, wherein a MACPDU is generated, and the MAC PDU includes a MAC header and a pluralityof MAC payloads for a plurality of WTRUs.

15. The method of embodiment 14 comprising retrieving a MAC payload fromthe MAC PDU based on corresponding control information in the MAC headeron a condition that a dedicated WTRU identity is detected in the MACheader.

16. The method as in any one of embodiments 11-15, wherein the groupWTRU identity is derived from the dedicated WTRU identity.

17. The method as in any one of embodiments 12-16, wherein the MACpayload is an individual MAC PDU for a particular WTRU.

18. A WTRU comprising a processor configured to receive a joint HS-SCCH,decode the joint HS-SCCH with a group WTRU identity, and receive aHS-PDSCH based on decoding on the joint HS-SCCH.

19. The WTRU of embodiment 18, wherein the joint HS-SCCH includes acommon part and WTRU-specific parts, and the common part includes commoncontrol information for WTRUs multiplexed in one TTI, and each of theWTRU-specific parts includes WTRU-specific control information for acorresponding WTRU.

20. The WTRU of embodiment 19, wherein each of the WTRU-specific partsincludes CRC bits masked with a corresponding WTRU identity.

21. The WTRU as in any one of embodiments 19-20, wherein all or part ofeach of the WTRU-specific parts is masked with a WTRU identity bits or abit sequence derived from the WTRU identity.

22. The WTRU as in any one of embodiments, 19-21, wherein the commoncontrol information is not masked with any identity.

23. The WTRU as in any one of embodiments 19-22, wherein all or part ofthe common control information on the common part is masked with groupWTRU identity bits or a bit sequence derived from a group WTRU identity.

24. The WTRU as in any one of embodiments 19-23, wherein the processoris configured to determine whether the common part of the joint HS-SCCHis directed to the WTRU based on a group identity, determine whether anyone of the WTRU-specific parts of the joint HS-SCCH is directed to theWTRU based on a WTRU-specific identity, and decode the HS-PDSCH usingthe common control information and the WTRU-specific control informationfor the WTRU.

25. A WTRU comprising a processor configured to receive an HS-SCCHincluding a group WTRU identity shared by a group of WTRUs.

26. The WTRU of embodiment 25 wherein the processor is configured toreceive an HS-PDSCH based on decoding on the HS-SCCH with the group WTRUidentity.

27. The WTRU of embodiment 25 wherein the processor is configured togenerate a MAC PDU including a MAC header and a plurality of MACpayloads for a plurality of WTRUs.

28. The WTRU of embodiment 25 wherein the processor is configured toretrieve a MAC payload from the MAC PDU based on corresponding controlinformation in the MAC header on a condition that a dedicated WTRUidentity is detected in the MAC header.

29. The WTRU as in any one of embodiments 25-28, wherein the group WTRUidentity is derived from the dedicated WTRU identity.

30. The WTRU as in any one of embodiments 25-29, wherein the MAC payloadis an individual MAC PDU for a particular WTRU.

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element can be used alone or in any combination with theother features and elements. In addition, the methods described hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable media include electronicsignals (transmitted over wired or wireless connections) andcomputer-readable storage media. Examples of computer-readable storagemedia include, but are not limited to, a read only memory (ROM), arandom access memory (RAM), a register, cache memory, semiconductormemory devices, magnetic media such as internal hard disks and removabledisks, magneto-optical media, and optical media such as CD-ROM disks,and digital versatile disks (DVDs). A processor in association withsoftware may be used to implement a radio frequency transceiver for usein a WTRU, UE, terminal, base station, RNC, or any host computer.

1. A method for multiplexing data for multiple wireless transmit/receiveunits (WTRUs) in a subframe, the method comprising: receiving, by aWTRU, a common control information message for a group of WTRUs timemultiplexed in one subframe, and a WTRU-specific control informationmessage for a corresponding WTRU, wherein the WTRU is part of the groupof WTRUs; determining, by the WTRU, whether the common controlinformation message is directed to the WTRU based on a group WTRUidentity; determining, by the WTRU, whether the WTRU-specific controlinformation message is directed to the WTRU based on a WTRU-specificidentity for the WTRU; receiving, by the WTRU, a physical downlinkshared channel on a WTRU-specific transmission time interval (TTI)within the subframe based on decoding of the common control informationmessage with the group WTRU identity, wherein the WTRU-specific TTI forthe WTRU is one of a plurality of WTRU-specific TTIs within the samesubframe; and decoding, by the WTRU, the physical downlink sharedchannel using the common control information message and theWTRU-specific control information message for the WTRU.
 2. The method ofclaim 1, wherein each WTRU-specific TTI is specific to a correspondingWTRU.
 3. The method of claim 1, wherein each WTRU-specific TTI isspecific to a plurality of corresponding WTRUs.
 4. The method of claim1, wherein the receiving the physical downlink shared channel is furtherbased on decoding the WTRU-specific control information with theWTRU-specific identity for the WTRU.
 5. The method of claim 1, whereinthe group WTRU identity is decoded using cyclic redundancy check (CRC)bits.
 6. The method of claim 1, wherein the WTRUs included in the groupof WTRUs is dynamically changed for each transport block.
 7. A wirelesstransmit/receive unit, part of a group of WTRUs, comprising: atransceiver operatively coupled to a processor, the transceiver and theprocessor configured to receive a common control information message forthe group of WTRUs time multiplexed in one subframe and a WTRU-specificcontrol information message for a corresponding WTRU, determine whetherthe common control information message is directed to the WTRU based ona group WTRU identity, determine whether the WTRU-specific controlinformation message is directed to the WTRU based on a WTRU-specificidentity for the WTRU, receive a physical downlink shared channel on aWTRU-specific transmission time interval (TTI) within the subframe basedon decoding of the common control information message with the groupWTRU identity, and decode the physical downlink shared channel using thecommon control information message and the WTRU-specific controlinformation message for the WTRU; and wherein the WTRU-specific TTI forthe WTRU is one of a plurality of WTRU-specific TTIs within the samesubframe.
 8. The WTRU of claim 7, wherein each WTRU-specific TTI isspecific to a corresponding WTRU.
 9. The WTRU of claim 7, wherein eachWTRU-specific TTI is specific to a plurality of corresponding WTRU. 10.The WTRU of claim 7, wherein the receipt of the physical downlink sharedchannel is further based on decoding the WTRU-specific controlinformation with the WTRU-specific identity for the WTRU.
 11. The WTRUof claim 7, wherein the group WTRU identity is decoded using cyclicredundancy check (CRC) bits.
 12. The WTRU of claim 7, wherein the WTRUsincluded in the group of WTRUs is dynamically changed for each transportblock.
 13. A method for multiplexing data for multiple wirelesstransmit/receive units (WTRUs) in a subframe, the method comprising:transmitting, by a base station, a common control information messagefor a group of WTRUs time multiplexed in one subframe, and aWTRU-specific control information message for a WTRU, wherein the WTRUis part of the group of WTRUs, wherein the common control informationmessage is directed to the WTRU based on a group WTRU identity and theWTRU-specific control information message is directed to the WTRU basedon a WTRU-specific identity for the WTRU; and transmitting, by the basestation, a physical downlink shared channel on a WTRU-specifictransmission time interval (TTI) within the subframe correlating to thecommon control information message with the group WTRU identity, whereinthe WTRU-specific TTI for the WTRU is one of a plurality ofWTRU-specific TTIs within the same subframe.
 14. The method of claim 13,wherein each WTRU-specific TTI is specific to a corresponding WTRU. 15.The method of claim 13, wherein each WTRU-specific TTI is specific to aplurality of corresponding WTRU.
 16. The method of claim 13, wherein thegroup WTRU identity is encoded using cyclic redundancy check (CRC) bits.17. The method of claim 13, further comprising dynamically changing, bythe base station, which WTRUs are included in the group of WTRUs foreach transport block.